The present invention relates generally to an apparatus for handling sheet material and, more particularly, to an apparatus for turning and inverting sheet material.
In the production of bent laminated glass products, such as present day automotive windshields for example, it is common practice to achieve the desired configuration by bending flat sheets of glass in pairs to the contour of a mold. Prior to the actual bending, the sheets are thoroughly cleaned and dried and a surface of at least one and preferably both of the sheets has applied thereto a coating of a water soluble parting material to prevent the sheets from fusing to one another when heated during the bending process. The sheets are then placed, one upon the other, with the parting material therebetween and their edges aligned in preparation for bending.
In a mass production operation, pairs of glass sheets are carried horizontally, or in the flat position, in a spaced relation on a conveyor through the various steps of the process including the step of inverting the first sheet of each pair and laying it upon the second sheet. Such an operation is disclosed in U.S. Pat. Nos. 3,034,632 and 3,067,853, assigned to the same assignee as the present invention.
While the sheet turnover apparatus disclosed in these patents are admirably suited for their intended purpose, they are designed to handle only one size of sheet at any given time and changeover for a run of differently sized sheets requires production line shutdown and delays to effect the necessary adjustments for accommodating differently sized sheets. It can be appreciated that this especially poses problems when handling sheets for jobber requirements, wherein only a limited number of any one size of paired sheets of a plurality of variously sized paired assemblies are processed for a short period of time.